1. Field of the Invention
The present invention relates to wheelchairs and, more particularly, to a brake system for a wheelchair.
2. Background Information
Currently, almost all wheelchairs use a side-mounted locking lever brake system that is operable by a user of the wheelchair (i.e. a seated person) in order to enable the user to more safely enter (i.e. sit) and leave the seat of the wheelchair. These conventional brake mechanisms typically consist of a pair of levers, each one engaging the exterior or outside periphery of the larger wheels of the wheelchair. To immobilize the wheelchair, the levers must be manually actuated to engage the wheels.
Albeit somewhat effective, this type of braking system is positioned such that is readily accessible only by the patient and since many patients are provided locomotion by an ancillary aid (i.e. person), the position of such brakes is not suitable for the person pushing the wheelchair. Moreover, this type of braking system is designed to immediately immobilize the large wheels of the wheelchair and thus the wheelchair, particularly for either maintaining a position of the wheelchair or for allowing a person to get into or out of the wheelchair, rather than provide a gradual braking system for the ancillary person guiding or pushing the wheelchair.
Furthermore, since many public areas like shopping centers are providing wheelchair ramps and since not everyone pushing a wheelchair is suitably strong enough to prevent a patient and his wheelchair from uncontrollably rolling down these ramps and other obstacles, it would be prudent to provide a braking or motion retardation system for the wheelchair that is used by an ancillary person controlling the motion of the wheelchair. Various solutions, such as the U.S. Patents discussed below, have been devised in order to address this issue. These systems, however, are inadequate for obvious reasons.
U.S. Pat. No. 3,529,700 discloses a brake assembly for a wheelchair that includes spring loaded brake elements mounted on the main frame of the wheelchair that are normally biased toward wheel engagement. The spring loaded brake elements are disengaged from the wheels in response to a seat controlled linkage (engages and disengages in response to a person sitting or not) or by a manually operative disengagement device. This system, however, is complicated with its various springs and levers. Moreover, the brake levers to be used by the ancillary person are awkwardly positioned.
U.S. Pat. No. 4,852,697 discloses a brake device for a wheelchair that is adapted to be engaged by a secondary operator of the wheelchair. The brake device includes a mounting bracket attached to a handle of the wheelchair and carrying actuator linkage (brake arm) coupled to an actuator tube and stopper. The actuator linkage moves the attached stopper in engagement with the rear wheel of the wheelchair to lock the wheel against rotation. Again, however, this brake system is complicated with its various linkage. Moreover, the handles for the actuator linkage that is used by the secondary operator are awkwardly positioned.
U.S. Pat. No. 5,667,236 discloses a control grip brake for a wheelchair that includes an internal steel sleeve adapted for rotatable coupling with an existing handle of a wheelchair. A steel spring coil applies a clockwise/counter clockwise tension on the internal steel sleeve. An outer hand grip is adapted for securement over the internal steel sleeve and is utilized to actuate a brake mechanism that is secured to a steel cable that is coupled with a wheel of the wheelchair.
This brake system thus applies the braking power through rotation of the hand grips. Since the hand grips are grasped with the palms of the hand facing inwardly and the backs of the hand facing outwardly, this also results in an awkward grasping and/or actuation position for the braking system.
U.S. Pat. No. 5,894,912 discloses a wheelchair braking device that is adapted to automatically engage when the wheelchair to which the device is mounted is unoccupied. This wheelchair braking device, however, utilizes a complex series of levers and interconnections therebetween. Moreover, this braking device positions a secondary or ancillary operator's hands in the typical awkward palms in and backside out position that is not conducive to allowing the hand to transmit sufficient torque for braking.
What is therefore needed in view of the above, is a motion retardation system for a wheelchair that is usable by a secondary or ancillary person.
What is therefore also needed in view of the above, is a selectively engageable motion retardation system for a wheelchair that may be operatively mounted at various locations on the wheelchair depending on the intended user of the motion retardation system.
What is therefore further needed in view of the above, is a brake system for a wheelchair that provides ergonomic positioning of a braking force application device particularly for pushing the wheelchair and applying a braking force thereto.
What is therefore still further needed in view of the above, is a brake system for a wheelchair which applies a sufficient braking force to the wheelchair for a given amount of applied braking force.
What is therefore even further needed in view of the above, is a brake system for a wheelchair that is usable by a secondary or ancillary person and which provides a simple, yet efficient transfer of applied braking force to the wheel structure of the wheelchair.